A delivery adapter may be used as an interface between a syringe and a catheter hub. The syringe may contain a liquid material, in particular a high viscosity liquid material such as liquid embolic. Liquid embolic can be thought of as biocompatible glue which can be used to fill various vascular malformations such as aneurysm, arteriovenous malformation, fistula, or other malformations. Liquid embolic can also be used for various occlusive purposes such as vessel shutdown, fallopian tube occlusion, or occlusion of the peripheral vasculature. The delivery adapter helps to minimize or even eliminate altogether the dilution of the viscous liquid material in the catheter used to deliver said viscous liquid material to a treatment site within the vasculature.